As some people have suggested, tire pressure adjustment might help. After I had the clutch changed and flywheel resurfaced on my 05 wagon, this decel noise reared its ugly head. I adjusted the tire pressure from 36psi all around (thank you lazy shop techs at costco) to 40psi fronts, 34psi rears, where I usually run them. This made the decel noise almost disappear completely. I should note that I have stock 16 inch rims and AS tires with no sidewall support. This is what i think caused MY noise. With the tires at even pressure, the fronts get squished more than the rears due to the engine weight, making the true wheel diameters different. the center diff has to deal with the different wheel rotation speeds front vs rear and loads the transmission in a direction that some of the bearings dont like, hence decel noise. With the tire pressure adjusted, all wheels the same diameter, no loading one way or the other in the tranny, the bearings spin freely, no decel noise.